1. Field of the Invention
The present invention relates to a charging apparatus used with a mobile robot and, more particularly, to a charging apparatus used with a mobile robot to recharge the mobile robot.
2. Description of the Related Art
Generally, mobile robots have been used in various industrial fields to maneuver elements or working tools, which are required to manufacture products, to desired positions.
Recently, there is a growing tendency to increase use of the mobile robots at home as well as in the industrial fields. At home, the mobile robot is used to clean a room, guard a user against attack, and protect the user's property.
The mobile robot is designed to fulfill given functions and missions within a scope of activity. Thus, the mobile robot is constructed to detect a moving direction and position thereof within the scope of activity. Further, the mobile robot has a rechargeable battery therein to supply electricity to various driving units including a motor to drive wheels of the mobile robot.
When the electricity available in the rechargeable battery falls below a predetermined level, the mobile robot moves to a charging unit to charge the rechargeable battery of the mobile robot. Generally, the mobile robot transceives signals with the charging unit and moves to a position adjacent to the charging unit. Thereafter, the mobile robot moves to be in contact with the charging unit, thereby forming an electrical contact between the rechargeable battery and the charging unit.
When the mobile robot moves to be in contact with the charging unit, a position error may occur due to obstacles disposed on a support surface between the mobile robot and the charging unit, or friction between the wheels and the support surface. At this time, the mobile robot fails to be in electrical contact with the charging unit. In this case, the mobile robot must move forward, backward, leftward, and rightward so as to be in electrical contact with the charging unit. The mobile robot repeats such trial and error until the electrical contact is successfully established. Thus, it takes a long time to charge the mobile robot, and further there may occur a failure to incompletely charge the rechargeable battery.
To solve the above problems, a method of installing a lamp in the charging unit to emit light has been proposed. Thus, the mobile robot moves to an electric contact (connection) position in response to the light emitted from the lamp. The above method has a problem in that the trial and error is only reduced while the failure of an electrical connection (contact) occurs frequently because the mobile robot approximately detects the electrical contact position. Therefore, the above conventional method is not practical.
To reduce the frequency of the failure of the electrical connection, there also has been proposed the charging unit and the mobile robot having an expensive guide unit. Because the mobile robot is controlled by the guide unit, the mobile robot comes into electrical contact with the charging unit at a higher rate. However, this conventional method of using the guide unit also has a problem in that it is uneconomical because the guide unit is expensive.